Title: The Complexity and Redundancy of Carbon Catabolite Repression in Pseudomonas

Presenter: Dr. Xue-Xian Zhang

University: Institute of Natural and Mathematical Sciences, Massey University, New Zealand

Time: 15:00-16:00, June 8, 2016

Venue: Room A203, Institute of Microbiology, Chinese Academy of Sciences

Abstract: Bacteria have strict food preferences in terms of the order in which they uptake and utilize substrates: the underlying mechanism being carbon catabolite repression (CCR). CCR has been well studied in E. coli where it is mediated by the catabolite-activating protein (CAP) charged with cAMP. However, this paradigm does not hold for many non-enteric bacteria, including those of the closely related genus Pseudomonas. Here Dr Zhang will present their current model of CCR in a plant growth-promoting bacterium P. fluorescens SBW25, which involves complex interactions among a two-component signal transduction system CbrAB, two non-coding small RNAs (CrcY and CrcZZ) plus the Crc and Hfq RNA binding proteins. Next, mathematical modelling has been employed to understand why such a complex CCR system has been evolved in Pseudomonas; e.g., why two functionally equivalent non-coding RNAs are involved. Finally, Dr Zhang will show that functional redundancy can also occur in an evolutionary manner in the case of bacterial utilization of succinate as the sole carbon source.